From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mukesh Rathor Subject: Re: [V6 PATCH 6/7] pvh dom0: Add and remove foreign pages Date: Thu, 5 Dec 2013 18:54:24 -0800 Message-ID: <20131205185424.5986673b@mantra.us.oracle.com> References: <1386297524-15483-1-git-send-email-mukesh.rathor@oracle.com> <1386297524-15483-7-git-send-email-mukesh.rathor@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1386297524-15483-7-git-send-email-mukesh.rathor@oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Mukesh Rathor Cc: george.dunlap@eu.citrix.com, Xen-devel@lists.xensource.com, tim@xen.org, keir.xen@gmail.com, JBeulich@suse.com List-Id: xen-devel@lists.xenproject.org On Thu, 5 Dec 2013 18:38:43 -0800 Mukesh Rathor wrote: > In this patch, a new function, xenmem_add_foreign_to_p2m(), is added > to map pages from foreign guest into current dom0 for domU creation. > Such pages are typed p2m_map_foreign. Also, support is added here to > XENMEM_remove_from_physmap to remove such pages. Note, in the remove > path, we must release the refcount that was taken during the map > phase. actually, now build break on arm with unused p2mt. So here's fixed up patch with modified include/asm-arm/p2m.h: ----------- In this patch, a new function, xenmem_add_foreign_to_p2m(), is added to map pages from foreign guest into current dom0 for domU creation. Such pages are typed p2m_map_foreign. Also, support is added here to XENMEM_remove_from_physmap to remove such pages. Note, in the remove path, we must release the refcount that was taken during the map phase. Signed-off-by: Mukesh Rathor --- xen/arch/x86/mm.c | 88 +++++++++++++++++++++++++++++++++++++++++---- xen/common/memory.c | 37 ++++++++++++++++++- xen/include/asm-arm/p2m.h | 2 + 3 files changed, 118 insertions(+), 9 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index e3da479..1a4d564 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -2810,7 +2810,7 @@ static struct domain *get_pg_owner(domid_t domid) goto out; } - if ( unlikely(paging_mode_translate(curr)) ) + if ( !is_pvh_domain(curr) && unlikely(paging_mode_translate(curr)) ) { MEM_LOG("Cannot mix foreign mappings with translated domains"); goto out; @@ -4520,9 +4520,75 @@ static int handle_iomem_range(unsigned long s, unsigned long e, void *p) return 0; } +/* + * Add frames from foreign domain to target domain's physmap. Similar to + * XENMAPSPACE_gmfn but the frame is foreign being mapped into current, + * and is not removed from foreign domain. + * Usage: libxl on pvh dom0 creating a guest and doing privcmd_ioctl_mmap. + * Side Effect: the mfn for fgfn will be refcounted so it is not lost + * while mapped here. The refcnt is released in do_memory_op() + * via XENMEM_remove_from_physmap. + * Returns: 0 ==> success + */ +static int xenmem_add_foreign_to_p2m(struct domain *tdom, unsigned long fgfn, + unsigned long gpfn, struct domain *fdom) +{ + p2m_type_t p2mt, p2mt_prev; + int rc = 0; + unsigned long prev_mfn, mfn = 0; + struct page_info *page = NULL; + + if ( tdom == fdom || !tdom || !fdom || !is_pvh_domain(tdom) ) + return -EINVAL; + + /* following will take a refcnt on the mfn */ + page = get_page_from_gfn(fdom, fgfn, &p2mt, P2M_ALLOC); + if ( !page || !p2m_is_valid(p2mt) ) + { + if ( page ) + put_page(page); + return -EINVAL; + } + mfn = page_to_mfn(page); + + /* Remove previously mapped page if it is present. */ + prev_mfn = mfn_x(get_gfn(tdom, gpfn, &p2mt_prev)); + if ( mfn_valid(prev_mfn) ) + { + if ( is_xen_heap_mfn(prev_mfn) ) + /* Xen heap frames are simply unhooked from this phys slot */ + guest_physmap_remove_page(tdom, gpfn, prev_mfn, 0); + else + /* Normal domain memory is freed, to avoid leaking memory. */ + guest_remove_page(tdom, gpfn); + } + /* + * Create the new mapping. Can't use guest_physmap_add_page() because it + * will update the m2p table which will result in mfn -> gpfn of dom0 + * and not fgfn of domU. + */ + if ( set_foreign_p2m_entry(tdom, gpfn, _mfn(mfn)) == 0 ) + { + gdprintk(XENLOG_WARNING, "set_foreign_p2m_entry failed. " + "gpfn:%lx mfn:%lx fgfn:%lx td:%d fd:%d\n", + gpfn, mfn, fgfn, tdom->domain_id, fdom->domain_id); + put_page(page); + rc = -EINVAL; + } + + /* + * We must do this put_gfn after set_foreign_p2m_entry so another cpu + * doesn't populate the gpfn before us. + */ + put_gfn(tdom, gpfn); + + return rc; +} + static int xenmem_add_to_physmap_once( struct domain *d, - const struct xen_add_to_physmap *xatp) + const struct xen_add_to_physmap *xatp, + struct domain *fdom) { struct page_info *page = NULL; unsigned long gfn = 0; /* gcc ... */ @@ -4581,6 +4647,13 @@ static int xenmem_add_to_physmap_once( page = mfn_to_page(mfn); break; } + + case XENMAPSPACE_gmfn_foreign: + { + rc = xenmem_add_foreign_to_p2m(d, xatp->idx, xatp->gpfn, fdom); + return rc; + } + default: break; } @@ -4646,7 +4719,7 @@ static int xenmem_add_to_physmap(struct domain *d, start_xatp = *xatp; while ( xatp->size > 0 ) { - rc = xenmem_add_to_physmap_once(d, xatp); + rc = xenmem_add_to_physmap_once(d, xatp, NULL); if ( rc < 0 ) return rc; @@ -4672,11 +4745,12 @@ static int xenmem_add_to_physmap(struct domain *d, return rc; } - return xenmem_add_to_physmap_once(d, xatp); + return xenmem_add_to_physmap_once(d, xatp, NULL); } static int xenmem_add_to_physmap_range(struct domain *d, - struct xen_add_to_physmap_range *xatpr) + struct xen_add_to_physmap_range *xatpr, + struct domain *fdom) { /* Process entries in reverse order to allow continuations */ while ( xatpr->size > 0 ) @@ -4693,7 +4767,7 @@ static int xenmem_add_to_physmap_range(struct domain *d, xatp.space = xatpr->space; xatp.idx = idx; xatp.gpfn = gpfn; - rc = xenmem_add_to_physmap_once(d, &xatp); + rc = xenmem_add_to_physmap_once(d, &xatp, fdom); if ( copy_to_guest_offset(xatpr->errs, xatpr->size-1, &rc, 1) ) return -EFAULT; @@ -4780,7 +4854,7 @@ long arch_memory_op(int op, XEN_GUEST_HANDLE_PARAM(void) arg) } rc = xsm_add_to_physmap(XSM_TARGET, current->domain, d, fd); if ( rc == 0 ) - rc = xenmem_add_to_physmap_range(d, &xatpr); + rc = xenmem_add_to_physmap_range(d, &xatpr, fd); rcu_unlock_domain(d); if ( fd ) diff --git a/xen/common/memory.c b/xen/common/memory.c index eb7b72b..7103c8b 100644 --- a/xen/common/memory.c +++ b/xen/common/memory.c @@ -675,9 +675,11 @@ long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg) case XENMEM_remove_from_physmap: { + unsigned long mfn; struct xen_remove_from_physmap xrfp; struct page_info *page; struct domain *d; + p2m_type_t p2mt = -1; if ( copy_from_guest(&xrfp, arg, 1) ) return -EFAULT; @@ -693,11 +695,42 @@ long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg) return rc; } + /* + * If autotranslate guest, (eg pvh), the gfn could be mapped to a mfn + * from foreign domain by the user space tool during domain creation. + * We need to check for that, free it up from the p2m, and release + * refcnt on it. In such a case, page would be NULL and the following + * call would not have refcnt'd the page. + * See also xenmem_add_foreign_to_p2m(). + */ page = get_page_from_gfn(d, xrfp.gpfn, NULL, P2M_ALLOC); if ( page ) + mfn = page_to_mfn(page); +#ifdef CONFIG_X86 + else { - guest_physmap_remove_page(d, xrfp.gpfn, page_to_mfn(page), 0); - put_page(page); + mfn = mfn_x(get_gfn_query(d, xrfp.gpfn, &p2mt)); + if ( p2m_is_foreign(p2mt) ) + { + struct domain *foreign_dom; + + foreign_dom = page_get_owner(mfn_to_page(mfn)); + ASSERT(is_pvh_domain(d)); + ASSERT(d != foreign_dom); + } + } +#endif + if ( page || p2m_is_foreign(p2mt) ) + { + guest_physmap_remove_page(d, xrfp.gpfn, mfn, 0); + if ( page ) + put_page(page); + + if ( p2m_is_foreign(p2mt) ) + { + put_page(mfn_to_page(mfn)); + put_gfn(d, xrfp.gpfn); + } } else rc = -ENOENT; diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h index c660820..ac109f8 100644 --- a/xen/include/asm-arm/p2m.h +++ b/xen/include/asm-arm/p2m.h @@ -110,6 +110,8 @@ static inline int get_page_and_type(struct page_info *page, return rc; } +#define p2m_is_foreign(_t) ( 0 && (_t) ) + #endif /* _XEN_P2M_H */ /* -- 1.7.2.3